Treatment of Slaughterhouse Plant Wastewater by Sequential Chemical Coagulation-Continuous Flow Electrooxidation Process

Wastewater from a small animal slaughterhouse (SWW) was treated by a two-step process: coagulation/flocculation (CF) followed by continuous flow electrooxidation (CFEO). Initially, a coagulant dose of 0.8 kg m −3 in the CF process, using FeCl 3 at pH 8.5, achieved 52% COD and 63% turbidity removal (effluent: 2000 mg l −1 and 65.2 NTU). Alum, (optimum pH = 6.5), yielded 50% COD and 55% turbidity removal (effluent of 2100 mg l −1 and 78.5 NTU). Subsequently, when employing the CFEO process following the CF process with FeCl 3 , the study achieved highly efficient results. Specifically, under optimum conditions (residence time in the CFEO reactor, τ = 240 min, wastewater feed rate to the reactor = 15 ml min −1 , and current density = 300 A m −2 ), the COD and turbidity removal efficiencies reached 99.60% (resulting in an effluent of 8 mg l −1 ) and 99.9% (resulting in an effluent of <0.10 NTU), respectively. In conclusion, the CF + CFEO consecutive treatment process demonstrated remarkable treatment efficiencies, with COD and turbidity removal rates of 99.9% and 99.9%, respectively. Moreover, the total operating cost of this treatment process was found to be 3.60 US $/m 3 .